Driving gear of multicylinder reciprocating-piston engines



, W..A. WILLIAMS DRIVING GEAR OP IUL'IIGYLINDBR RSCIPROCATING-PISTON ENGINES May 17, 1949.

3 Sheets-Shoot 1 mm m; '20, 1946 May 17, 1949.

DRIVING GEAR OP IUL'I'ICYLINDER RBOIPROCATING-TISTON ENGINES Filed F613. 20, 1946 3 Sheets-Sheet 2 w. A. WILLlAMS 2,470,669 I May 17, 1949. w. A. WILLIAMS DRIVING GEAR OF IUL'IICYLINDER RICIPROGATING-PISTON ENGINES Filed Feb. 20, 1946 s Sheets-Shut s Patented May 17, 1949 DRIVING GEAR F MUL IcyL nEa RECIPROCATING-PISTON ENGINES William Arthur Williams, London, England Application February 2 0, 1946, Serial No. 648,938

In Great Britain September 5,1944 a:

Section 1,Public'LaW- 690, August 8, 1946 Patent expires September 5, 1964 Claims. (01. 121-417) This invention relates to the driving gear of multi-cylinder reciprocating piston engines and it has for its objectt'o provide'an improved construction of crankshaft mechanism which is exceptionally efficient and which is particularly suitable for employment in multi-cylinder engines.

It is a furtherobjec't of the invention to provide an improved engine of the general form described in my British Patent Specification No. 533,047 in which a number of mutually parallel pistons are connected with a cross-head member having an oblique cam track engaged by a follower upon a crankpin so that reciprocation of the pistons and cross-head member brings about rotation of said crankpin.

In a multi-cylinder engine comprising a plurality of pistons slidable within corresponding mutually parallel cylinder bores and coupled with a cross-head member having a cam track lying at an inclination to the cylinder axes, said cam track being connected with a rotatable crankpin so that as the latter moves around its orbit the cross-head memberand pistons reciprocate as one, the invention is characterised by the fact that the crankpin is connected with the cam track by a carriage device comprising a body Which is pivoted to the crankpin and which carries a plurality of rollers engaging the cam track at spaced positions.

Preferably the rollers of the carriage device are disposed at opposite sides of the crankpin axis, the body of the carriage device conveniently being elongated and the crankpin being disposed substantially halfway along the length of said body. The distance of the crankpin axis from the surface of the cam track can advantageously be substantially equal to the radius of the crankpin orbit thus where the axes of the crankpin and the rollers all lie in a common plane the diameter of the rollers of the carriage are preferablysubstantially equal to the diameter of the crankpin orbit.

The cross-head may be formed with a plurality of substantially fiat treads which are engaged by corresponding flat surfaces upon the ends of the pistons, the pistons being connected with the cross-head, each by a pair of link members dis: posed one on each side of the corresponding tread,

said link members having a pin and transverse.

slot connection at one end to allow the piston. to move laterally relative to the cross-head member in aligning itself with its cylinder bore. If desired the cam track may be provided upon a flange formed along the edge of the cross-head member, the carriage device being provided with retaining means which engage the rear surface of said flange to prevent the carriage device from moving away from the cam track to a substantial extent.

The pistons are preferably hollow and are closed at their ends adjacent the cross-head member each by a plug which engages with said crosshead member. The pistons connected with the cross-head member can be of progressively increasing length, their working faces being disposed in a common plane at right angles to the cylinder axes, while their opposite outer ends lie each roller.

in a line substantially parallel with the cam track,

Preferably the carriage body is divided in the plane of the cylinder axes, into two parts accommodating respectively the two end bearings of a recess, the inner part of which constitutes half a crankpin bearing, the other half of said bearing being formed upon a block which is secured within the recess, the block being arranged to fit snugly between the sides of the recess in the carriage body so as to strengthen the body as regards bending due to the force transmitted between the cam track and the crankpin. The rollers may be recessed at their ends to accommodate annular bearing flanges upon the parts of the carriage body, the outer operative surfaces of the rollers thus being wider than the distance between the said bearing flanges. If desired the pistons and w cylinders may form the sole guiding means for the cross-head member.

"" der engine or engine unit;

Figure 2 is apart sectional fragmentary View taken on the line 22 of Figure 1, drawn to an enlarged scale and showing the link connection device between a piston and the cross-head member;

Figure 3 is an elevation of one of the links.

shown in Figure 2;

Figure 4 is a fragmentary sectional view through the carriage, taken on the line 4-4 of Figure 1 and drawn to an enlarged scale; and

Figure 5 is a fragmentary view showing in-elevation another arrangement of engine in whichthe cross-head member is guided independently,

of thevpistons.

The engine unit shown in Figure 1 comprise I a water-jacketed cylinder block IEI having four mutually parallelcylinder bores ll, I2, 13 and M, the cylinder bores II and I2 beinglengtheneddownwards by forming thecylinder block 10 with Thus the carriage body may have 3 tubular extensions |5 and IS. The cylinder block I is mounted upon a crank case comprising a base portion I1 and an upper portion l8, a horizontal crank shaft l9 having its axis in the plane of separation of the parts I1 and I8 and being formed with a crankpin 20.

Disposed within the crank case l1 and I8 is a cross-head member 2 l' which is formed along its under side with a cam track 22 arranged at a substantial inclination, preferably 45 with respect to the axes of the cylinder bores ||-i4. The cross-head member 2| is connected positively with four pistons 23, 24, 25 and 26 which are arranged to reciprocate in the bores l2, l3 and I4 respectively and which are provided at their upper ends with the usual piston rings indicated at 21. Each of the pistons 23-26 is hollow and is in fact of inverted cup shape, the pistons having their lower ends closed by means of flanged plug members 28, 29, 30 and 3| respctively, these being secured in position by bolts or screws (not shown). The lower part of each plug member 283| is formed with a flat surface which'is indicated at 32 and is arranged to bear against a corresponding horizontal tread upon the cross-head member 2|, said tread being shown at 33, 34, 35 and 36. The pistons 2326 are I positively connected with the cross-head member 2| each by a pair of links 31 and 38 which are arranged in the manner shown in Figure's 2 and 3. Each of the links has at its upper part a hole 39 for the reception of a shouldered bolt 40 by which it is secured to the corresponding piston plug (say 29) while at its lower part the link has a transversely extended hole or slot 4| 'by which said link is arranged to be secured to the cross-head member 2| by a shouldered bolt 42', The length of the links 31 and 38 is such that the fiat surface 32 upon the bottom of the piston is retained in smooth sliding engagement with the corresponding tread (say 34) upon the cross-head member 2|, the slots 4| enabling the piston to move slightly in a lateral direction so as 'toslide truly within the corresponding cylinder bore. In the case of the longest piston 23, however, the cross-head member 2| is formed with upwardly extending shoulders or abutments 43 and 44 at the respective ends of the tread 33, thus positively locating the cross-head member 2| with respect to the piston 23 so that the latter serves as an efficient guide for locating the cross head member 2| throughout its reciprocating movement. It is found that the provision of the flat treads 34, 35 and 36 effectively maintains the cross-head member 2| at the correct inclination for which it is designed. It will of course be understood that in Figure 1 the usual cylinder head, valve gear and ignition or injection means of the engine have been omitted as these form no part of the present invention and can be of any form to suit the type of engine to which the improved crank mechanism is applied.

The cross-head 2| is operatively connected with the crankpin 20 and the crank shaft l9 by means of a carriage device which is indicated generallyat 50. It comprises a carriage body which is formed in two parts and 52 as will be seen'in'the cross sectional view constituting Figure 4, the parts 5| and 52 being arranged to abut together in a vertical plane 53 coinciding with the axes of the cylinders |||4 The two parts are held together firmly by bolts 54 and at their inner part they are both cut away to form a substantially U-shaped recess, the side Walls of which are indicated at 55 and 56. The bottom part 51 of this recess is of semi-cylindrical shape and is arranged to fit around the upper part of the crankpin 20 so as to provide a rotatable bearing. A block 58 is fitted snugly into the recess defined by the walls 55 and 56, said block being shaped at its upper part with a semi-cylindrical surface 59 arranged to fit against the lower part of the crankpin 20 so as to complete the bearing surface. The block 58 is secured in position by bolts 60. It will thus be seen that the carriage body 5|, 52 is snugly rotatable upon the crankpin 20 and it can be readily assembled on said crankpin owing to the provision of the removable block 58.

At its two end parts the carriage body 5|, 52 has its mating surface hollowed for the reception of four'bearing rollers 6|, 62, 63 and 64, these rollers being arranged to run upon the cam track 22 and being each mounted in the manner shown in Figure 4, which of course shows a section through the roller 6|, a rim portion 65 having an outer working surface 66 which is substantially wider than the centre part 91 of the roller. spindle 63 projecting from both sides into a pair of bearing bushes 69 and mounted in the body parts 5| and 52 respectively; these bushes constitute tubular bearings extending inwards as far as the centre part 61 of the roller, i. e. further inwards than the corresponding edge of the 7 working surface so that by this means the carriage is made very compact and at the same time each roller is provided with a wide peripheral working surface and with sturdy central bearings of generous area.

It will be seen in Figure 4 that the lower part of the cross-head member 2| is enlarged in width to form a relatively wide cam track 22, the enlargement constituting a pair of longitudinal flanges II and 12. These are used for retaining the carriage member 55 at all times in engagement with the cross-head member 2| and for this purpose the parts 5| and 52 of the carriage body are fitted along their upper edges withv strips 13 and 14 respectively arranged to fit snugly upon the flanges II and 12. It should be pointed out that during the normal running of the engine the carriage member 50 always tends to remain in firm engagement with the crosshead member 2|, as, during the power stroke,

the pistons |||4 press the carriage member 55 downwards while on the upward stroke the crank shaft l9, through the carriage body 50,

presses the pistons upwards; the strips 13, 14 however are usually required to bring about the reciprocation of the pistons during starting.

In order to secure the smoothest and most eflicient action of the crank mechanism it is desir: able that the carriage device 50 should be designed so that the distance of the axis of the crankpin 29 from the cam track 22 measured at right angles to the latter should be substantially equal to the radius of the orbit of the crankpin i. e. the distance of the crankpin axis from the axis of the crank shaft l9. Where the axes of the rollers (SI-64 all lie in a plane which contains also the axis of the crankpin 20 it follows that the diameter of the rollers should be equal to the diameter of the crankpin orbit in order to satisfy the above condition.

In the modified form of engine crank mechanism shown in Figure 5, side thrust on the crosshead member 2| due to the wedging action of the" oblique cam track 22 is resisted by the engagement of the left hand edge 80 of the cross-head The roller is shaped with I The latter has an integral member slidable within a groove 8! formed in a guide member 82 constituting the side wall of the crank chamber. It will be seen that the crosshead member 2! is in this case roughly triangular in form so as to provide a relatively long guiding edge 30. Two pistons 23a and 24a, are slidable within cylinder bores Ila and He and they have their lower ends connected as before with the cross-head member 2! by means of pairs of links 31 and 38 arranged to hold the lower ends of the pistons snugly in engagement with flat treads 33a and 34a upon the cross-head member 2|. The crankpin 29 of the crank shaft I9 is again fitted with a carriage device indicated at 50a, but in this instance the carriage device has only two rollers shown in dotted lines at 62a. and 63a. The body of the carriage device We is moreover formed in two parts 83 and 84 which are joined together along the plane containing the axes of the rollers 62a and 63a and the crankpin 20, the parts being held together firmly by bolts 85. With this arrangement the two parts 83 and 84 can be hollowed out to receive the rollers 62a, 63a and also shaped to form divided bearings for the spindles 68a of said rollers; it has the disadvantage, however, that the thrust from the pistons is transmitted by the rollers to the lower part 84 of the carriage body and is thus imparted to the upper part 83 of the crankpin 20 through the medium of the bolts 85. The carriage device 58a is maintained in working contact with the cross-head member 21 by longitudinal strips 13 and 14 which are arranged to engage with the upper surface of corresponding flanges II and 12 formed upon the cross-head member 2 l Although the assemblies shown in Figures 1 and 5 may by the use of a flywheel be used as an engine, it will be understood that normally such assemblies would be used in pairs, the carriages being mounted on crankpins disposed 180 apart so as to obtain an effective balance.

It will be understood, moreover, that the arrangements which have been described are given merely by way of example and that various modifications are possible. Thus, any number of pistons can be provided in conjunction with a single cross-head member and a number of such cross-head members may be used in conjunction with a single crank shaft, separate crankpins suitably disposed being provided. The invention can, of course, be used in any type of reciprocating engine such as steam engines and internal combustion engines generally. In some multicylinder internal combustion engines it will be found to be advantageous and economical to shut off fuel from certain cylinders when the full power of the engine is not required.

What I claim is:

1. A multi-cylinder engine comprising a plurality of cylinders disposed side by side, a plurality of pistons slidable in said cylinders, a single crosshead member connected to said pistons and arranged to reciprocate as one therewith, a straight cam track formed on the crosshead member and extending at a substantial inclination to the cylinder axes, a single crankshaft, a crankpin on said crankshaft disposed adjacent the cam track, and a carriage device operatively connecting the crankpin with the crosshead member and which includes a body pivotally mounted on the crankpin and a plurality of rollers, pivoted upon the body to roll along the cam track as the pistons reciprocate.

2. An engine as defined in claim 1, wherein the distance of the crankpin axis from the cam surface is equal to the radius of thecrankpin orbit,

3. An engine as defined in claim 1, wherein the pistons connected with the crosshead member are of progressively increasing length so that their front ends lie in a common plane perpendicular to the cylinder axes and their rear ends engage the inclined crosshead member.

4. An engine as defined in claim 1, wherein the carriage body comprises two parts abutting together in the plane of the cylinder axes, bearings for one end of each roller being formed in one part and bearings for the other end of each roller being formed in the other part.

5. An engine as defined in claim 1, wherein, the carriage body comprises a block fitting into a recess at the center of said body, a bearing for the crankpin being formed half in the body and half in the block.

6. A multi-cylinder engine comprising a plurality of cylinders disposed side by side, a plurality of pistons slidable in said cylinders, a single crosshead member connected to said pistons and arranged to reciprocate as one therewith, a straight cam track formed on the crosshead member and extending at a substantial inclination to the cylinder axes, a single crankshaft, a crankpin on said crankshaft disposed adjacent the cam track, and a carriage device operatively connecting the crankpin with the crosshead member and which includes a body pivotally mounted adjacent its center upon the crankpin, and a plurality of rollers pivoted to the body at both sides of the crankpin to engage the cam track at spaced positions and roll along said cam track as the pistons reciprocate.

7. An engine as defined in claim 6, wherein the body of the carriage is elongated and the crankpin is disposed substantially midway the length of said body.

8. A multi-cylinder engine comprising a plurality of cylinders disposed side by side, a plurality of pistons slidable in said cylinders, a single crosshead member connected to said pistons and arranged to reciprocate as one therewith, a plurality of substantially fiat treads in descending succession down the crosshead member, each being in line with, and perpendicular to, the axis of one of the corresponding cylinders, a fiat surface upon the corresponding piston engaging said tread, a straight cam track formed on the crosshead member and extending at a substantial inclination to the cylinder axes, a single crankshaft, a crankpin on said crankshaft disposed adjacent the cam track, and a carriage device operatively connecting the crankpin with the crosshead member.

9. An engine as defined in claim 8, wherein a pair of link members connect each piston with the crosshead member, said link members being disposed one on each side of the corresponding tread, a pin and transverse slot connection being provided at one end to allow the piston to move laterally relative to the crosshead member in aligning itself with the cylinder bore.

10. A multi-cylinder engine comprising a plurality of cylinders disposed side by side, a plurality of pistons slidable in said cylinders, a single crosshead member connected to said pistons and arranged to reciprocate as one therewith, a straight cam track formed on the bottom of the crosshead member and extending at a substantial inclination to the cylinder axes, a lateral flange formed along the whole length of the crosshead member extending the cam track laterally, a single crankshaft, a crankpin on said crankshaft disposed adiacent the cam track, and

5e device operatiVeIy connecting the ii'rarikpinwim the eros'shead member and which REFERENCES CITED includes abodyfiivotallymounted on the crank- The following references are of record in the iiih, a plur'ality of rollers pivoted on the body to file of this patent: 'riiI-l alohgthe surface of the cam track, and. re- 5 taming means on the body engaging the upper UNITED STATES PATENTS surface of the lateral flange to keep the rollers Number Name D in Contact withthe cam surface. 3,6 Felies Sept. 15, 1931 FOREIGN PATE'N ARTHUR WILLIAMS. 10 Ts Number Country Date 322,090 Germany June 11, 1920 

